Eleven days from now, most federal agencies will be forced to shut down, unless Congress can agree on a stopgap funding bill. Prospects for a shutdown rose sharply yesterday, after House Republicans decided to try passing a funding measure that would defund President Obama's health care law. Now, in the past, Senate Republican leader Mitch McConnell has helped to resolve this kind of standoff. But it would be harder for McConnell to jump in this time.

NPR's David Welna explains.

DAVID WELNA, BYLINE: House Speaker John Boehner earlier had opposed to tying a continuing resolution keeping the government's lights on to a measure crippling the health care law. But yesterday, he bowed to hardliners in the House's unruly GOP ranks who've been pushing for precisely that.

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REP. JOHN BOEHNER: We're going to continue to do everything we can to repeal the president's failed health care law. This week, the House will pass a CR that locks the sequester savings in and defunds Obamacare.

WELNA: And then, Boehner added, it would be up to the Democratic-led Senate to approve the stopgap measure.

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BOEHNER: It is time for the Senate to have this fight.

WELNA: But the Senate's number three Democrat, New York's Chuck Schumer, called the House GOP plan defunding Obamacare insane. Senate Democrats, he added, would never go along with it.

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SEN. CHARLES SCHUMER: We're not going to blink. You can't be held hostage. You can't have someone put a gun to your head and say: We're going to do horrible, ridiculous things unless you give in to us. And so we're standing firm.

WELNA: The votes of at least half-a-dozen Senate Republicans would be needed to amend the House bill and restore the funds stripped from the healthcare program. Asked Tuesday where he and his fellow Republicans stood, Senate Minority Leader Mitch McConnell said they all agreed Obamacare was the worst piece of legislation in the last 50 years.

SEN. MITCH MCCONNELL: I think it's safe to say every Republican thinks it was a huge mistake and would like to get rid of it.

WELNA: But McConnell did not say how he would vote on a House bill that defunds Obamacare.

MCCONNELL: We will react to what they send us and be happy to vote on it at that point.

WELNA: As McConnell spoke to reporters, just down the hallway, the Senate's number-two Democrat, Dick Durbin, sized up the Republican leader.

SEN. DICK DURBIN: I think Senator McConnell is in a very delicate position.

WELNA: And this is McConnell's position. Back in his home state of Kentucky, where he's seeking reelection, he's facing a Tea Party-backed challenger who strongly endorses defunding Obamacare. At the same time, a standoff over Obamacare leading to a government shutdown - or possibly to a default, if the debt ceiling isn't raised next month - could badly damage Republicans' chances of taking back control of the Senate in next year's midterm elections.

Durbin says McConnell is in a no-win situation.

DURBIN: And I think, at this point, that he has basically backed off from playing a leadership role in resolving the budget and debt ceiling issues.

WELNA: That was not the case as recently as the end of December, when McConnell stepped up to head off the fiscal crisis.

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MCCONNELL: I want everyone to know I'm willing to get this done. But I need a dance partner.

WELNA: That dance partner turned out to be Vice President Joe Biden. But Duke University congressional expert David Rohde says since then, McConnell's dance partner has been Kentucky's junior Senator and a Tea Party favorite, Rand Paul.

DAVID ROHDE: McConnell has Rand Paul's support right now. But that's not a guarantee that the rank-and-file Tea Party people will stick with McConnell.

WELNA: Unlike Paul, McConnell did not sign a letter this summer circulated by Tea Party-aligned Senate Republicans that vowed not to approve any funding for Obamacare. He's being castigated for that in a TV ad that's been playing in Kentucky, paid for by a group called the Senate Conservatives Fund.

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UNIDENTIFIED ANNOUNCER: Obamacare starts in October, but Congress can stop its funding. What's Mitch McConnell doing? Nothing. McConnell is the Senate Republican leader, but he refuses to lead on defunding Obamacare. What good is a leader like that?

WELNA: McConnell, who's been in the Senate nearly three decades, would not be interviewed for this report. But Senate expert Ross Baker of Rutgers University says McConnell may still have some tricks up his sleeve.

ROSS BAKER: There are options that Senator McConnell has. He's not entirely painted himself into a corner. And I suspect that he has probably thought this through pretty thoroughly.

WELNA: But if McConnell does have a plan to thread this needle, he has yet to show it.